three-mesh-bvh
Version:
A BVH implementation to speed up raycasting against three.js meshes.
128 lines (82 loc) • 2.49 kB
JavaScript
import { Vector3 } from 'three';
export class SeparatingAxisBounds {
constructor() {
this.min = Infinity;
this.max = - Infinity;
}
setFromPointsField( points, field ) {
let min = Infinity;
let max = - Infinity;
for ( let i = 0, l = points.length; i < l; i ++ ) {
const p = points[ i ];
const val = p[ field ];
min = val < min ? val : min;
max = val > max ? val : max;
}
this.min = min;
this.max = max;
}
setFromPoints( axis, points ) {
let min = Infinity;
let max = - Infinity;
for ( let i = 0, l = points.length; i < l; i ++ ) {
const p = points[ i ];
const val = axis.dot( p );
min = val < min ? val : min;
max = val > max ? val : max;
}
this.min = min;
this.max = max;
}
isSeparated( other ) {
return this.min > other.max || other.min > this.max;
}
}
SeparatingAxisBounds.prototype.setFromBox = ( function () {
const p = new Vector3();
return function setFromBox( axis, box ) {
const boxMin = box.min;
const boxMax = box.max;
let min = Infinity;
let max = - Infinity;
for ( let x = 0; x <= 1; x ++ ) {
for ( let y = 0; y <= 1; y ++ ) {
for ( let z = 0; z <= 1; z ++ ) {
p.x = boxMin.x * x + boxMax.x * ( 1 - x );
p.y = boxMin.y * y + boxMax.y * ( 1 - y );
p.z = boxMin.z * z + boxMax.z * ( 1 - z );
const val = axis.dot( p );
min = Math.min( val, min );
max = Math.max( val, max );
}
}
}
this.min = min;
this.max = max;
};
} )();
export const areIntersecting = ( function () {
const cacheSatBounds = new SeparatingAxisBounds();
return function areIntersecting( shape1, shape2 ) {
const points1 = shape1.points;
const satAxes1 = shape1.satAxes;
const satBounds1 = shape1.satBounds;
const points2 = shape2.points;
const satAxes2 = shape2.satAxes;
const satBounds2 = shape2.satBounds;
// check axes of the first shape
for ( let i = 0; i < 3; i ++ ) {
const sb = satBounds1[ i ];
const sa = satAxes1[ i ];
cacheSatBounds.setFromPoints( sa, points2 );
if ( sb.isSeparated( cacheSatBounds ) ) return false;
}
// check axes of the second shape
for ( let i = 0; i < 3; i ++ ) {
const sb = satBounds2[ i ];
const sa = satAxes2[ i ];
cacheSatBounds.setFromPoints( sa, points1 );
if ( sb.isSeparated( cacheSatBounds ) ) return false;
}
};
} )();